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Satellite data from Landsat Thematic Mapper (TM) were used to derive sea surface temperature (SST) in coastal waters of Hsinta that receive cooling effluent from a power plant. Ground truth temperatures measured simultaneously from a ship as Landsat passed were used to compare with the satellite results.
Two methods were applied to improve the atmospheric correction process for monitoring SST. Local radiosonde measurements, used in Lowtran7 adjustments for atmospheric effects, produced corrected ocean surface radiances and atmospheric transmittances. The mean deviation between the ship-measured and satellite estimated SST is 0.94℃ if the atmospheric correction process is applied compared with over 7℃ if that process is negleted. Secondly, a scheme combining NOAA Advanced Very High Resolution Radiometer (AVHRR) and Landsat-TM was used to derive SST. The advantage of this scheme is that no atmospheric correction process is required. The mean deviation between the ground truth and satellite-derived SST from this scheme is 1.01℃ for thermal plume of Hsinta power plant and 0.62℃ for Tseng-Wen estuarine waters, respectively.
With Landsat''s good resolution and proper use of the atmospheric correction process as suggested in this study, it can be used to locate power plant discharge and intake positions, to investigate the distribution of thermal plumes, and to estimate the surface temperatures of coastal waters, large rivers, lakes and estuarine waters. The combination of AVHRR and TM to estimate SST around the outfall of power plant proves to be a promising and convenient way.
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